Pregnancy and diabetes

Question 1

Why is it important to be vigilant for gestational hyperglycaemia?

Answer 1

Diagnosing maternal hyperglycaemia allows prevention of disease
- it may prevent morbidity in the offspring, an exacerbation of the obesity and T2DM epidemic and future T2DM in the mother

Impaired glucose tolerance in pregnant women = DM and should be treated as such

Question 2

Outline the differences between pre-gestational hyperglycaemia and “gestational diabetes”

Answer 2

PRE-GESTATIONAL HYPERGLYCAEMIA

• T1DM, T2DM
• Monogenic diabetes
• Impaired glucose tolerance

GESTATIONAL DIABETES
- any newly found abnormal glucose tolerance after the 1st trimester of pregnancy

Question 3

What is the WHO criteria (and NICE) for diabetes OR impaired glucose tolerance?

Answer 3

• fasting glucose ≥ 5.6 mmol/L

- 2 hour glucose tolerance test ≥ 7.8 mmol/L

Question 4

Outline the key developmental changes occuring in utero during the 1st, 2nd and 3rd trimester

Answer 4

1st trimester

• organogenesis: carefully design the essential components and avoid teratogenesis
• construct and programme the pacenta

2nd trimester
- further complex development and linkage

3rd trimester
- accelerated growth

Question 5

What are the physiological changes that occur during early and late pregnancy regarding glucose metabolism?

Answer 5

EARLY PREGNANCY = FACILITATED ANABOLISM

• Increased insulin sensitivity
• Glucose concentration slightly lower
• Increased maternal energy stores

LATE PREGNANCY = FACILITATED CATABOLISM

• Increased insulin resistance
• Increased transplacental passage of nutrients –>rapid foetal growth

Question 6

State 3 examples of foetal malformation

Answer 6

• hydrocephalus
• meningomyelocoele
• central cyanosis in congenital heart disease
• single ventricle and sacral dysgenesis
• renal dysgenesis

Question 7

What is the relationship between maternal HbA1C and congenital malformation?

Answer 7

Women with diabetes have higher HbA1c

- the higher this is, the greater the percentage of congenital malformation

Question 8

Why is it important to have good maternal diabetes control?

How can this be achieved?

Answer 8

Really important in first trimester, involved pre-pregnancy counselling (life style modification, intensive glucose monitoring, optimise insulin regimen, start insulin if not already on it)

+ Folic acid 5mg/day before conception

Primary care can help prevent foetal malformation by identifying cases of DM and IGT by screening women with Rx factors (ethnicity, previous gestational diabetes, obesity, PCOS, FHx of T2DM)

Question 9

What do NICE guidelines say about screening of pregnant women

Why is Metformin good at managing diabetes?

Answer 9

Only screen at 26 weeks those at high risk

Metformin can help decrease weight which increases the efficiency of insulin but lifestyle has a greater effect.

Question 10

What problems may occur in the third trimester?

Lifelong foetal sequelae?

How prevalent are these issues?

Answer 10

• Macrosomia and associated problems - leads to difficult birth should dystocia, breathing problems, jaundice and hypoglycaemia
• Pre-eclampsia
• Foetal or neonatal death: women with T2DM x9 perinatal mortality, T1DM x4
• Lifelong foetal sequelae ? obesity, insulin resistance, T2DM, dyslipidaemia, hypertension, vascular disease

1/5 women in the UK are obese at antenatal booking

Question 11

What does treatment of gestational hyperglycaemia look like?

Answer 11

• Good materal glucose control, intensive b/g monitoring
• Appropriate nutrition
• Reasonable exercise
• Ultrasound monitoring of foetal abdominal girth (monthly from 28 weeks)
• Maternal observation of foetal movements
• Pre-pregnancy/1st trimester basal bolus insulin regimen
• “Gestational” diabetes = metformin, basal insulin/basal bolus insulin, Glibenclamide

Question 12

What are the targets of treatment of pregnancy hyperglycaemia?

Answer 12

Fasting glucose< 5.1 mmol/L

1 hour postprandial glucose < 7 mmol/L

Foetal abdominal girth < 70th percental (less in asians)

Question 13

What does continued management of pregnancy hyperglycaemia postpartum look like?

Any advice specific to GDM?

Answer 13

• Maintain good glycaemic control to prevent glucose in milk and reduce maternal weight gain
• Advice
• Contraception advice (until HbA1c low): POP, COCP (after 6 weeks)
• Encourage breast feeding: reduces postpartum weight gain and decreases risk of DM
• Screen for diabetes at 12 weeks post partum (HbA1c, fasting glucose, GTT)
• Review GAD
• Annual glucose screening